diff --git a/setup.py b/setup.py
index 953d398..6050e57 100644
--- a/setup.py
+++ b/setup.py
@@ -37,6 +37,7 @@ setup(name='plone.app.discussion',
           'Framework :: Plone',
           'Framework :: Plone :: 5.0',
           'Framework :: Plone :: 5.1',
+          'License :: OSI Approved :: GNU General Public License (GPL)',
           'Programming Language :: Python',
           'Programming Language :: Python :: 2.7',
       ],